The bill would increase the federal minimum wage, currently at $7.25, to $15 by 2024, and tie future increases to the median wage growth. It would also gradually eliminate the current exception to the minimum wage for tipped workers.

"Just a few short years ago, we were told that raising the minimum wage to $15 an hour was 'radical,'" Sanders said. "Our job in the wealthiest country in the history of the world is to make sure that every worker has at least a modest and decent standard of living."

Sanders kicked off the hearing by charging that the budget's repeal of the estate tax would give massive breaks to the country's wealthiest families -- including President Trump's family, which he estimated would save $4 billion, and the Walton family of Walmart fame, which he said would save $52 billion.

Sanders asked Mulvaney to explain why America's richest family needs a $52 billion tax break, while people who rely on programs such as Meals on Wheels and Medicaid would be left out in the cold under Trump's budget.

He also expressed anger that Republicans were impugning the work of Congressional Budget Office Director Keith Hall, even though he was appointed by Republicans.

More administration officials on the budget: Thursday was the second day in a row in which Mulvaney and Treasury Secretary Steven Mnuchin testified before Congress on President Trump's budget and tax proposals. Some highlights:

The proposal to tax imports and exempt exports has been facing long odds for several months, with retailers, conservative groups and senators warning that it would lead to consumers paying more for items such as clothes and groceries.

But in recent weeks and days, the concerns have been mounting from the White House and House Republicans.

Senators air grievances on Trump energy budget, delays: Senators of both parties used a Thursday hearing on a trio of energy-related nominees to the Trump administration to criticize the president's policies and the delays in approvals by a federal agency.

Members of the Senate Energy and Natural Resources Committee lodged few, if any, complaints against the three nominees before them: Dan Brouillette to be the deputy secretary at the Department of Energy (DOE), and Neil Chatterjee and Robert Powelson to be members of the Federal Energy Regulatory Commission.

Instead, the panel sought assurances that their states' priorities would be protected if the nominees were confirmed.

The hearing came two days after President Trump unveiled his first budget proposal, which included deep cuts to many programs at the DOE, especially those related to renewable energy and energy efficiency.

Senate takes lead on Trump's infrastructure proposal: The Senate is taking the lead on President Trump's effort to move a massive infrastructure package through Congress.

Top GOP lawmakers in the upper chamber are pushing ahead with plans that could serve as the building blocks for negotiations on the president's initiative following the first real glimpse of Trump's $1 trillion infrastructure proposal this week.

Survey concludes US must do better job of promoting interests abroad: A majority of registered voters say the United States must do a better job of promoting the nation's interests at international organizations like the United Nations, according to a new survey released Thursday.

The survey shows that 76 percent of respondents want U.S. leaders to focus on policies that help Americans while a similar majority -- 75 percent -- say the United States must remain part of the U.N. and other international groups to protect against policies that could cost manufacturing jobs here, according to the data compiled by Morning Consult.

OPEC to extend oil production cuts: OPEC agreed on Thursday to extend its oil production limits for at least the next nine months as a way to ensure higher crude prices.

Delegates at an Organization of the Petroleum Exporting Countries (OPEC) gathering in Vienna decided to maintain the production cuts they initially implemented late last year, Reuters reports.

Members of the 13-country organization, as well as a dozen non-members including Russia, will likely abide by the output limits, according to Reuters.

OPEC initially decided to cut production levels last December, when a sustained global supply glut and increasing production from non-OPEC members -- including the United States -- caused oil prices to sag. A barrel of crude oil cost over $100 in July 2014; by February 2016, the price briefly dipped below $27.

The December agreement -- when OPEC producers decided to cut output by 3.7 percent, to 32.5 million barrels per day -- was the first production limit instituted by OPEC since 2008. In the months that followed, prices rose to over $58 per barrel.